Work hold-down for jointers



Sept. 3, 1957 R. E. PETERSON WORK HOLD-DOWN FOR JOINTERS 2 Sheets-Sheet1 Filed Sept. 13, 1954 INVENTOR RusselZE. Peiersan.

Sept. 3, 1957 R. E. PETERSON 2,304,392

WORK HOLD-DOWN FUR JOINTERS Filed Sept. 15, 19,54 2 Sheets-Sheet 2INVENTOR RussellE Peierson BY HTTYS United States Patent Ofiice2,804,892 Patented Sept. 3, 1957 WORK HOLD-DOWN FOR J OlINTERS RussellE. Peterson, Turlock, Calif.

Application September 13, 1954, Serial No. 455,710

3 Claims. (Cl. 144-242) This invention relates to attachments topower-driven wood-working tools, particularly tools of the type known asjointers.

Considering a jointer, for which my device has been especially designed,such a tool includes front and rear tables, spaced apart, and a rotarycutter head exposed in the space between the tables. While jointers asnow marketed are provided with a guard over the cutter head, this isonly effective when the tool is not in use, and no Work hold-down deviceis provided. By reason of this arrangement, the hands must be used toboth advance and press down the work over the cutter head, and since theguard is pushed aside by the work as it advances, the cutter head isexposed directly under the work and the hand holding down such work.Serious cutting of the fingers frequently results.

The principal object of my invention is to eliminate the above describeddangerous feature of a jointer by the provision of a device which servesas an eflicient hold-down means for the work as it is advanced, and alsoforms a guard over the cutter head. The use of the hands to hold downthe work as it passes over the cutter head is therefore renderedunnecessary, and the possibility of finger or hand cutting iseliminated.

The device includes work-engaging hold-down blades, and another objectof the invention is to arrange and mount the blades so that constantpressure on the work, regardless of its thickness, will be exertedthereon as it passes over the cutter head, and without any adjustment onthe part of the operator being necessary.

A jointer includes a fence, and another object of the invention is to somount the device on the fence that it may be swung up out of the waywhen desired, as for cleaning of the tables and other parts of thejointer when the same is not in use, or for edge jointing work.

It is also an object of the invention to provide a work hold-down forjointers, which is designed for ease and economy of manufacture.

A still further object of the invention is to provide a practical,reliable, and durable work hold-down for jointers, and one which will beexceedingly effective for the purpose for which it is designed.

These objects are accomplished by means of such structure and relativearrangement of parts as will fully appear by a perusal of the followingspecification and claims.

In the drawings:

Fig. 1 is a front end elevation of the work hold-down device, as mountedon a conventional jointer as fragmentarily and diagrammatically shown.

Fig. 2 is a side view of the device, as in operation, partly broken awayand in section.

Fig. 3 is a top plan view of the device, detached.

Referring now more particularly to the drawings, and to the charactersof reference marked thereon, the improved work hold down device, as hereshown, is designed for mounting on a conventional jointer which includesa front table 1, a rear table 2 spaced somewhat from table 1, a rotarycutter head 3 exposed between the tables, and a fence 4 upstanding fromthe tables at one side thereof.

The work hold-down devicecomprises a bar 5 which rests on top of thefence in the longitudinal zone of the adjacent separated ends of thetables, and such bar is secured to the fence by bolts 6. Upstanding fromthe bar 5 intermediate its ends are cars 7 serving as supports for thepivot bolts 8 of the adjacent side of a transversely extending frame 9which overhangs the table unit of the jointer.

The frame 9 includes horizontal transverse bars 10 spaced lengthwise ofthe jointer, and which are integrally connected at their outer end by abar 11. Another bar 12 connects the bars 10 above the same andintermediate their ends, and an ear 13 upstands from the bar 12centrally between the bars 10. A yoke 14 is pivoted on the car 13 and isrigid with a rod 15 extending transversely over the bar 5 and releasablyengaging in the upper end notch 16 of a boss 17 upstanding from the bar5. The adjacent end portion of the rod 15 is threaded and is fitted withan adjustable retaining nut 18 which engages the back side of the boss,and a holding nut 19 on the front side of the boss.

By reason of this feature, the frame 9 is normally held rigid, while itmay be adjusted so that the lower edge of the work-engaging members(later described) may be maintained accurately parallel to the tables ofthe jointer, or it may be swung up to a position well clear of thetables and cutter head, as indicated in dotted lines in Fig. 1.

Depending from the bars 10 of the frame 9 are substantially identicalbut independent work hold-down blades 20 which extend transversely ofthe tables for substantially their full width and terminate adjacent thesame; one blade normally overlying the table 1 and the other bladeoverlying the table 2.

Alined eyes 21 are rigidly secured on each blade along its upper edge,to register with lugs 22 depending from the adjacent frame bar 10; apivot pin 23 projecting through the lugs and eyes and pivoting theblades on the frame for swinging movement lengthwise of the jointer.

A torque spring 24, which may be of a well-known adjustable type, isdisposed about each pin 23 between eyes 24, and at one end engages thecorresponding blade and at the other end engages a stop 25 arranged infixed connection with the bar 12 in such a manner as to resist rotationof the blade in the direction of the rear end of the jointer.

Unwinding of each spring, so that the same is maintained under apredetermined normal load, is prevented by means of a stop 26 formedwith and depending from the related bar 12 and engaging thecorresponding blade 20 adjacent its upper edge and on the front sidethereof.

Each blade is rigid in itself; all yieldability being had by reason ofthe spring-resisted pivot mounting thereof, and each such blade isformed with a convex curvature in the direction of the forward end ofthe jointer; i. e., the end from which the work 27 approaches the cutterhead, as shown in Fig. 2.

In operation, the hold-down blades normally hang in a depending positionagainst the stops 26, and the cutter head 3 is shielded both from thefront and back by the rigid blades whichtogether with the mounting frame'aboveform a protecting hood over the danger zone.

When the work 27 is advanced on table 1 toward the cutter head 3, theforward end of such work engages the curved face of, and deflects, thefront hold-down blade 20, causing the latter to swing rearwardly andupwardly about its pivot pin 23 as an axis, and yet always presenting acurved surface against the top of the work.

The thicker and heavier the work, the greater will be the deflection ofthe blade, and the more the corresponding spring 23 will be loaded,resulting in a more forceful hold-down action onthe work, as willbeevident. Su-ch defiec tionof the front blade 20 places the hold-downpressure directly over the cutter'head and where most needed.

The pressure is maintained on the work as it advances onto table 2l'byengagement with, and similar deflection of, the rear hold-down blade 29.Once" the work is engaged by both hold-down blades 20, it is onlynecessary for the operator to impart an advancing motion to the work,and the hands need not belpresseddown on the work close to thecutterhead, as is at present required.

Thus, with my improved work hold-down and guard device, not only is thework firmlyheld down on the :tables as it moves past the cutter head,but the'danger'of accidents, caused by possible slippage'of thework andthe otherwise exposed rapidly rotating cutter head, is eliminated.

The convex curvature of the blades is an important factor in theeflicient hold-down action of the blades 20, since as the thickness ofthe work increases and the blades are swung further up, the curvedsurface of the blades, rather than the lower edge thereof, engages thework. The point of engagement is thus shifted closer to the pivot pin 23to compensate'for the :greater torsioning of the spring caused by suchgreater upward'swing. Also, such point remains close to a position overthe cutter head.

For use when the device is installed on 'a heavyduty j'ointer having awider fence, the mounting bar isformedginterrnediate its ends, with alaterallyproject-ing'boss "28 tapped to receive a set screw 29 to engagethe wider top flange of the fence, as indicated. This set screw -givesadded stability to the overhanging frame and takes some of the strainoff the holding bolts 6, which must resist the'tendencyof the frametoraise as the blades are deflected and swung up.

While the device is herein described as used'in connection with ajointer, it is also adaptable to other types of wood working tools whichinclude a rotary cutting element; as-for examplea shaper or'a circularsaw.

From the foregoing description it Willbe readily seen that there hasbeen produced such a device as-willsubstantially fulfill the objects ofthe inventiongas set forth herein. I 7

While this specification sets forth in detail the'present and-preferredconstruction of the device, still in practice such deviations therefrommaybe resortedto as do not form a departure from the spirit of theinvention, as defined by the appended claims.

Having thus described the invention the following is claimed as new anduseful, and upon which Letters Patent are desired:

l. A work hold-down attachment for a wood working tool'whic'h includesa' table unitand a rotary cutting member mounted intermediate the endsthereof, said attachment comprising a fixed frame disposed above andextending transversely of the table unit adjacent and above the cuttermember, a spring-urged work engaging blade mounted on and depending fromthe frame in an initial position with its lower :edgeoverhanging thetable unit adjacentthemem'ber, the tool having a-tence upstanding fromone side of the table unit, mounting means for the frame comprising abar extending along the top of the fence and secured thereon, meanspivoting the frame on the barfor swinging movement about a horizontalaxis lengthwise of the fence,:.and a reieasable brace connection betweenthe frame and bar normally maintaining the frame rigid with the bar.

2. A device, as in claim 1, with means to adjust the operative length ofthe brace so as to act on the frame and maintainthe lower-edge of theblade parallel with the table.

3. A work hold-down attachment for a wood working moi which-inel-udesatable unit, a rotary cutting member projecting up throughtheunit from below the same, and a -fence upstanding from one side of thetable unit and having aflatitop 'edge; said attachment comprising aframe above'andnormally extending transversely of the table unitadjacent the cutter member and latchable in such position, a work=engaging blade extending transversely of a-ndrnountedon an'd dependingfrom the frame in position to engage work advancing toward the cuttingmember, a bar extendingalong and resting on said top edge -of the fence,means pivoting the frame on the bar for swingingmovement of the framewhen unlatched about an axis parallebto =the'bar, and bol-tssecuring thebar-ion .the'fence.

References Cited inthe file'ofthis patent v 5 UNITED STATES PATENTS

